Modern vehicles typically have one or more diagnostic systems, generally having separate computer control modules to control various functions of the vehicle. Some examples include a powertrain control module (PCM), an engine control module (ECM), a transmission control module (TCM), an anti-locking brake system (ABS), and an air bag control module. The vehicle diagnostic systems often have self-diagnostic capabilities to detect and alert the driver of problems that the vehicle may be encountering. When a problem is found, a diagnostic trouble code (DTC), is set within the computer's memory. DTCs are as general or as specific as the manufacturer desires.
To retrieve and decipher DTCs, an auto repair technician needs a diagnostic tool, such as a scan tool. The scan tool is connected to the vehicle's computer bus system via a data link connector (DLC) to access and retrieve the DTCs. Scan tools are testing devices that interface with vehicle diagnostic systems to retrieve information from the various control modules. Scan tools are equipped to communicate in various communication protocols such as Controller Area Network (CAN), J1850 VPM and PWM, ISO 9141, Keyword 2000 and others. These communication protocols may be specific to each of the various vehicle manufacturers. The scan tool will help the technician to diagnose and repair the vehicle based on the information the tool retrieves from the vehicle.
The scan tools include computer software which must be periodically updated depending on the make and model of the vehicle to be serviced. In addition, the scan tool computer software may need to be updated from time to time as improvements in the software are made. Presently, many scan tools are FLASH programmed over a wired communication connection. FLASH programming a scan tool over wired communication connections is cumbersome because a user is required to bring the scan tool to a personal computer, and physically connect the scan tool to the personal computer.
A scan tool is physically connected to a personal computer with a cable. Cables vary in length depending on the particular application, but their maximum lengths are limited by their internal resistances associated with the conductors in the cables. Presently, there are cables that can link a scan tool and a personal computer when the two devices are separated by twenty feet. These cables require maintenance as the insulation surrounding them can deteriorate depending on whether they are properly cared for. In addition, the conductor within the cable may be broken within the cable if the cable is put in a high traffic area when it is continuously stepped on or driven over by a vehicle. Finally, requiring that the scan tool be physically connected to the PC limits the range that a technician can be from the personal computer and still update the scan tool.
Accordingly, it is desirable to provide a method and apparatus that allows a scan tool to be FLASH programmed over a wireless communication connection in order to eliminate the need for a cable and to extend the distance that one can operate a scan tool from a personal computer.